package com.baicaoyuan.web.common;

/**
 * 功能描述:
 *
 * @author 于骏
 *         创建时间 2017/5/17
 */
public class ValidationCodeUtil {

    /**
     * 生成验证码
     *
     * @param numberFlag 是否只有数字
     * @param length     验证码长度
     * @return
     */
    public static String generate_validation_code(boolean numberFlag, int length) {

        String retStr = "";
        String strTable = numberFlag ? "1234567890" : "1234567890abcdefghijkmnpqrstuvwxyz";
        int len = strTable.length();
        boolean bDone = true;
        do {
            retStr = "";
            int count = 0;
            for (int i = 0; i < length; i++) {
                double dblR = Math.random() * len;
                int intR = (int) Math.floor(dblR);
                char c = strTable.charAt(intR);
                if (('0' <= c) && (c <= '9')) {
                    count++;
                }
                retStr += strTable.charAt(intR);
            }
            if (count >= 2) {
                bDone = false;
            }
        } while (bDone);

        return retStr;
    }


}
